The general acceptance of industry automation as an essential requirement for improving productivity has increased the acceptance of the robot as a mechanism for achieving automated industrial applications. Numerous robotic configurations have been designed to meet specific industrial needs, for example, cutting, welding, assembly, material handling, etc. The designs of many commercially available robots are unique to a particular application and employ complex mechanical design features and sophisticated control functions dedicated to the specific industrial application.
A robot must be able to reach work pieces and tools. Typically, this requires a combination of an arm and a wrist subassembly plus a hand which is commonly called an end effector. The robot's sphere of influence is based upon the volume or sphere of influence into which the robot's arm can deliver the wrist subassembly. A variety of geometric configurations have been studied and tried and the relative kinematic capabilities appraised. Each of the several geometric configurations offers a different shape to its sphere of influence, the total volume of which depends upon the arm link lengths. For different applications, different configurations are typically appropriate. A revolute arm might be best for reaching into a container, while a cylindrical arm might be best suited to a straight thrust between the dies of a punching press.
In any event, the arm carries a wrist assembly mounted thereon to orient its end effector as required by workpiece placement. Commonly, the wrist provides three articulations that offer motions labeled "Pitch", "Yaw" and "Roll". It is common practice for any of the arm coordinate systems to use up to three articulations to deliver the wrist assembly anywhere into a sphere of influence. In addition to this, it is the common practice to require three more articulations in the wrist for universal orientation of the end effector.
It is an object of this invention to provide a modular multi-flange robotic wrist which provides one or two independent, controllable, degrees of freedom to enhance the basic motions of a robotic manipulator.
It is a further object of this invention to provide a robotic wrist with the capability to turn a part upside down with the axis of rotation of the part coincident with either axis of rotation of the wrist.
It is thus another object of this invention to eliminate the need for a three-axis wrist in the majority of robotic applications.
It is yet another object of this invention to provide a modular one- or two-axis multi-flange robotic wrist.